Metallic arc welding nozzle



July 14, 1942. w. E. SMITH METALLIC 4ARG WELDINGNZZLE Filed MarCh 27,1941 m v m mm mm .wm mm .smuw

*lidi Nm Y mm E um Patented July: 1K4, 1942 METALLIC ARC WELDING NOZZLEWilliam E. Smith, Detroit, Mich., assgnor to The Midland Steel ProductsCompany, Cleveland, Ohio, a rcorporation of Ohio Application March 2.7,1941, Serial No. 385,492

9 Claims.

tion thereto in order to reduce arcing, burning,

flash accumulation and wear, to the very minimum.

Another object of the invention is to completely insulate one of theconductors for the electrical energy to thev wire, from the nozzle andto completely insulate the wire guide in the nozzle tip from the nozzleto reduce arcing and -burning between the wire and the tip, and toprevent the accumulation of ilash on the tip and around the feed orificetherethrough.-

Other objects and advantages of the invention will become apparentduring the course of the following description.

In the accompanying drawing forming a part' of the application andwherein like numerals are employed to designate like parts throughoutthe several views,

Fig.\l is a side elevation of the improved nozzle,

Fig. 2 is a longitudinal section through the same taken on the line 2-2of Fig. 1,

Fig. 3 is a transverse section taken on the line 3- 3 of Fig. 2,

Fig. 4 is an enlarged longitudinal section of the tip end of the nozzle,

Fig. 5 is a transverse section of the same taken.

on the line 5-5 of Fig. 4.

To appreciate the full import of the problem involved, it is necessaryto comprehend the unusual high speed of welding performed by theapparatus. As stated in my copending application Serial No. 370,498 ledDecember 1'7, 1940, a welding head is disclosed which lays a weldbetween'parts at the rate of around 140 inches per minute using amperageas highV as 700 amps, and approximately 50 volts. This means that thefusible electrode wire passes through the nozzle at a rate ofapproximately 54 inches per minute. The wire is furnished with a roughor knurled external surface to increase traction and electricalconductance and its eiTect upon all parts with which it contacts, issimilar to the passage of a rat-tail file thereover. This naturallywears the parts severely and widens the electrical gap between them andthe wire, to the wire and other detrimental velects to cause4 stop-`page of the apparatus'for repairs and replacement.

Referring now more particularly to the drawing in detail, the numeral 6designates a cylindrical g in the split end 8 of a tubular holder 9 bythe extent of causing arcing, sticking of the electrode provision of apair of ears I0 on the opposed edges of the slit II, with oppositelyextending screws I2 threadedTthrough the ears to squeeze the split endof the holder firmly about the reduced end of the nozzle body.` Thisholder 9 is provided at its inner end with a reduced extension I3 onwhich a collar I 4 is secured, as by welding I5 to the holder. Thiscollar is provided with an upstanding ear having an orifice I6 extendingtransversely to the longitudinal dimension of the holder for theattachment of the lead of an electrical conductor for Supplyingelectrical energy to the nozzle, or it may be used to assist in themounting of the nozzle. The free end of the holder 9 is externally screwthreaded as at Il for attaching the holder to tha welding head or to aguide table, in a manner well understood in the art. The holder 9 isprovided with an enlarged longitudinal bore I8 of a diameter exceedingmany times the diameter of the metallic arc welding wire or electrodeII9 to be fed longitudinally therethrough. The holder 9, may, if desired,be constructed of insulating material in which event the welding currentcan be led into the nozzle and wire as will be described hereinafter.

The nozzle body 6 is provided with a longitudinally extending bore 20several'times larger than the diameter vof the wire I9 to preventcontact therewith and accidental arcing, and this bore at the outer endof the nozzle is enlarged as at 2| and at its extreme end is providedwith internal screw threads 22. 2I of the bore is provided at one sidewith a rectangular recess or seat 23 to snugly receive an electricalcontact block 24 of good electrical conducting material such as copperor a copper alloy. This contact block extends into the enlarged boresuch distance as to engage the electrode wire I9 and hold it spaced fromand centralized with respect to the bores 20 and I8. The surface of thecontact block which engages the wire is provided with a longitudinallyextending arcuate groove 25 to embrace approximately onehalf of thediameter of the welding wire. The conductor block is provided with acentral threaded opening to receive a screw 26 extending through Theenlarged portion the nozzle body 6 for rigidly fastening the conductor'in'place in its seat or recess. If desired, an electrical lead can besecured to this screw 26 for the conduction of electrical energy intothe contact piece 24 and thus into the welding wire I9. This conductorblock is arranged close to the work-end of the nozzle and the free endof the weldv wire to minimize heating of the wire and nozzle as well asto get the source of electrical energy as close as possible to the Work.

In order to firmly-press the wire I9 into contact with the groove 25 ofthe conductor block 24 to insure proper electrical contact andconduction'and to preclude any possible arcing between the wire and anyportions of the nozzle,

the latter is provided with a transverse opening 21 extending from theenlarged bore all the way through the exterior surface of the nozzle,and

pressure means designated in general by the numeral 28 is 'positioned inthis recess with good clearance therein for engagement with the weldwire I9. This pressure means is composed of a block of insulation 29freely movable in the opening 2'I4 and having its inner face providedwith a removable hardened steel contact block 30 removably secured tothe insulating block by means of the counter-sunk screws 3| in theinsulation block. To prevent any possible looseness or accidentalturning of the block 30 with respect to the insulation. block, thelatter is provided with a longitudinally extending channel, as bestshown in Fig. 3 for seating of the block 30 therein. In

' order to urge the pressure block inwardly of the opening 21 and theblock 30 into firm engagement with the Wire, a stiff fiat spring 32 issecured to the center of the pressure block by means of the screw 33andv the other end of the spring is secured to the nozzle 6 by the screw34. This spring has an. offset portion as shown and it is normallystressed by the wire passing between the blocks 24 and 30 so that thelatter firmly presses the wire into firm electrical contact with theconductor block 24. By having only one live contact engaging the wireI9, to one side of the nozzle, there 'is 'absolutely no arcin'g betweenthe pressure block or pad and wire or between it and the nozzle bore inwhich it operates, dueto the great spacing Athereof and its insulatingqualities.

v The outer end of the nozzle 6 has threaded therein a sleeve 35 of goodconducting material such as copper or a copper alloy. The outer end ofthis sleeve projects beyond the outer end of the nozzle to threadedlyreceive a tip 36 which is electrically insulated from' the end of thenoz'- zle by an insulating washer 3l. This tip is provided With la `bore38 in .which the electrode wire I9 has slight clearance to avoid theexcessive wear which the wire would impose on this opening in its rapidfeeding therethrough. The tip 36 is also counter-bored to receive andclamp therein a wear resisting electrode guide sleeve 39 through whichthe electrode is fed. ThisY guide sleeve has only very light tolerancebetween it and the wire I9 and is preferably made from stellite orhardened steel to resist the wear from abrasion of v.the wire in passingtherethrough at high speeds. This guide sleeve 39 is insulated from thetip and sleeve 35,by means of .its being positioned within an insulatingsleeve 40 with insulating washers 4| and 42 disposed at the ends of theguide sleeve 39 within the tip to completely insulate the sametherefrom. At the same time, the inner insulating washer 42 providesample insulation between. the two sleeves 35 and 39 thereby completelyelectrically isolating the hardened guide sleeve 39. Thus, since theprimary guide sleeve 39 is completely insulated on the tip and nozzle,there is removed all danger of arcing between the electrode and theguide sleeve and sticking of the electrode which heretofore has been asevere point of vulnerability of previous noz'zles which have been triedin this high speed welding operation. Also, since there is only one livecontact or conductor block employed in the nozzle, all danger of arcingand sticking at this point is likewise eliminated. Since the weldingwire is effectively held spaced from other parts ,of the nozzle, thelife of the tip and nozzle has been tremendously increased. Since thetip 36 is completely insulated from the nozzle, the excessively weldingflash from high speed welding is precluded, to a large degree, fromadhering to the tip and interfering with the smooth feed of the Wiretherethrough as it is consumed in the work.

If desired, the entire nozzle and tip 36 including theattachment sleeve35 and holder 9 may be constructed of hard insulating material such asBakelite Vor thelike with only the conductor block 24 constructed ofmetal or good conducting material, in which the electrical current isled into this conductor block through the screw 26. Since the borethrough such nozzle of insulating material is much larger than thediameter of the weld Wire fed therethrough which is held in spacedrelation to the walls of the bore by the arrangement of the conductorblock, pressure means and hardened guide sleeve 39 holding the wirecentralized in the bore and free of contact therewith, no abrasive wearwill be imposed upon the nozzle bore by the wire. y

As another alternative, the nozzle may be constructed of metal with theattachment sleeve 35 constructed of electrical insulating material suchas Bakelite, in which event the tip 36 could be constructed of likematerial with a hardened f metallic wear resisting guide sleeve 39positioned therein, in which event the insulating tube 40 r and washers3l, 4I and 42 could be eliminated.

However, in View of the fact that it is desired to pass the electriccurrent into the weld wire as' close to its free end as possible, theuse o f a metallic attachment sleeve 35 is very desirable. To furtherrealize this desirable point, the conductor block 24 and pressure means28 may be'located closer to the free end of the nozzleand substantiallywhere the attachment sleeve 35 is located, thereby eliminating thenecessity of the use of the attachment sleeve entirely. In suchmodification, the tip 36 could be provided with an integral threadedshank to thread into .the end of the nozzle or any other suitable formof attachment coul-d be employed. It is to be understood that variouschanges in the size, shape and i arrangement of parts may be restortedto without departing from the spirit of the invention or the scope ofthe appended claims.

I claim:

1. A metallic arc welding nozzle comprising a member having alongitudinally extending' bore of a diameter llarger thaln the weldingwire veying electrical current to the wire and assisting in supportingit clear of the bore.

2. A metallic arc welding nozzle comprising a member having alongitudinally extending bore of a diameter Ilarger than the weldingwire passed therethrough, and'a wear resisting sleeve associated'withsaid nozzle completely insulated i therefrom and having a guide openingfor the wire to hold the latter spaced from the walls of said bore.' 3.A metallic arc welding nozzle comprising a member having alongitudinally extending bore of a diameter larger than the welding wirepassed therethrough, an externally threaded sleeve ofinsulating materialthreaded into the end of the nozzle, a tip threaded on said sleeve, aninsulating washer between the tip and the end of the nozzle, and saidtip having a wear resisting sleeve therein with an opening just slightlylarger thanthe diameter of the wire to hold the same spaced from theWalls of said bore to prevent arcing and burning of the tip.

Y 4. A metallic arc welding nozzle having a longitudinal bore ythroughwhich the welding wire is fed in spaced relation to the walls of thebore,

aconductor-arranged in said bore in contact 'with the wire, pressuremeans insulated from the nozzle and serving to press the wire into goodelectrical contact with the conductor, and a guide for the wire in saidbore insulated therefrom and being highly resistant to abrasive actionof the wire passing therethrough and serving in conj junction with theconductor to space the wire from the bore-to prevent arcing between thewire and nozzle.

5. A metallic arc welding nozzlehaving a 1ongitudinal bore through whichelectrode wire` is fed, a -sleeve of insulating material threaded intothe end of the bore at the end of the nozzle and extendingpbeyond thefree end thereof, a tip threaded on to the end of said sleeve and ahardened metallic guide in said tip insulated therefrom to resistabrasive action of the wire passing therethrough. Y'

6. A metallic arc welding nozzle through which electrode wire is fedlongitudinally, an electrical conductor in said nozzle for slidingcontact with said wire, and a Wear resisting guide in said nozzlethrough which the wire passes, said guide being insulated from theconductor to prevent arcing and burning.

7. A metallic arc welding nozzle'through which electrode wire is fedlongitudinally, an electrical conductor in said nozzle for slidingcontact with said wire, an insulating tube in said nozzle, a wearresisting guide in said tube through which said wire passes, andinsulating washers abutting the ends of said guide to completelyinsulate the same from the nozzle.

8. A metallic arc welding nozzle having a bore extending longitudinallythereof and a lateral opening extending transversely from said bore tothe external surface of the nozzle. a removable electrical conductorfixedin said bore opposite said lateral opening and over which weldingwire slides in passing 'through said bore. and a pressure member ofinsulating material spring supported in said lateral opening and inspaced rela,-

tion to all walls thereof and carrying a hardened metallic piece topress the wire into contact with said fixed electrical conductor.

9. A metallic arc welding nozzle having a bore extending longitudinallythereof and a lateral opening extending transversely from said bore tothe external surface of the nozzle, a removable electrical conductorfixed in said bore opposite said lateral opening and over which weldingwire slides in passing through said bore, a pressure member Aoi'insulating material `in said lateral opening spaced from the wallsthereof, and a iiat spring fastened by an adjusting screw at one end tosaid nozzle andat its opposite end to said pressure member to urge thelatter against the wire and press it into contact withsaid fixedelectrical conductor.

WILLIAM E. SMITH.

